As a transmission device used in a pulsed radio communication system, for example, a transmission device described in Japanese Laid-Open Patent Publication No. 2006-303705 has been disclosed. In the transmission device mentioned above, a rectangular signal (a pulse signal) which is generated from an XOR circuit using a delayed clock signal is applied to a transmission signal generating section in which, then, the applied signal is modulated using a data signal and is output as a transmission signal. An RF switch configured to turn on/off the pulse signal in accordance with the data signal is used in the transmission signal generating section. As long as the frequency band for use in a pulsed radio communication system is on the order of the magnitude of microwave bands, no serious problem may occur. However, if the frequency band reaches the magnitude of millimeter wave bands exceeding 30 GHz, wide-band and high-speed switching characteristics will be demanded for the RF switch. However, a wide-band and high-speed RF switch is highly costly and large-sized, so that the size and the manufacturing cost of a transmission device using the RF switch of this type are increased.